Ellen Pompeo, Kate Burton Ellen Pompeo, Kate Burton

It's a true Throwback Thursday edition of Grey's Anatomy this week, with all kinds of new information about Ellis Grey (Kate Burton) and her relationship with Richard (James Pickens Jr.) coming to light.

How did everyone feel about all the flashbacks? Personally I wasn't a fan of the ones that were intercut — very jarringly, I might add — with present-day scenes. But it was nice to see Ellis and Richard's relationship play out, and to finally get some answers about Ellis' suicide attempt. Also, Baby Meredith!:

Anyway, to recap: The episode opens with Meredith (Ellen Pompeo) watching old home movies of a speech her mother gave, in which Ellis discusses the problems she's faced as a woman in a male-dominated field. Meredith's feeling a little misandrist herself, with Derek (Patrick Dempsey) demanding an explanation as to why his wife decided to get day-drunk with Alex (Justin Chambers), and Meredith retorting that she doesn't owe Derek anything just because he decided to stay in Seattle, and declaring that she's no longer going to measure her accomplishments against his. "You sound just like your mother," he hurls in her face. Somebody get Meredith a sweater, because that was cold.

(Side note: Speaking of questionable parenting decisions, should we put out an AMBER Alert for Bailey and Zola? Do Meredith and Derek use a 24-hour off-screen day care? Mysteries.)

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In a flashback to 1983, Young Richard and Young Ellis are boning. (IS THIS WHEN MAGGIE WAS CONCEIVED?!) He wants to put an end to their affair, worried that they'll get caught. She doesn't.

Present day: Alex and Stephanie (Jerrika Hinton) have a testy exchange in the elevator and we learn that, after losing the spot on the board, Alex got re-hired as a peds surgery attending; it's basically a consolation prize. And, apparently Arizona (Jessica Capshaw) lied to Alex that the board vote was close, while telling Bailey the truth — that it was unanimous in her favor. Whoops. Later, Meredith drops some hard truth on a pissy Alex, bluntly telling him that his speech was good but she wasn't about to give him a pity vote over Bailey (Chandra Wilson). Note to Alex: Being Meredith's person does not come with unconditional professional support. When he confronts Arizona, she says she needs Alex in peds to fill her shoes while she's doing the Geena Davis Fellowship (and trying to keep her marriage intact).

Meanwhile, Maggie (Kelly McCreary) says she's quitting, and the other docs are concerned about the "PR nightmare" of having another surgeon leave so quickly after Cristina. Webber is resigned to (if not a little bit happy about?) the news, while new board member Bailey is determined to make Maggie stay and get this "clown car" back on track.

It's time to practice some medicine! This week's case seems instantly upsetting: A 10-year-old girl has been abandoned outside the hospital because she appears to be going into labor (!!!). Wait, nevermind. She just has a mass the size of a soccer ball in her stomach. "Oh, thank God," says Stephanie. "That was getting dark." For once, I 100 percent agree with Stephanie.

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Elsewhere in the hospital, Amelia (Caterina Scorsone) — who's also against Maggie leaving — calls Derek in to help with a surgery talk Maggie out of resigning. Maggie awkwardly realizes that Meredith hasn't told Derek that they're sisters. (Amelia's "How we doin'?! Oh" in the middle of this conversation killed me.) After Maggie saves the day by pulling a MacGyver move on the patient's heart, we get the Derek and Amelia Shepherd Vaudeville Act: Amelia does verbal somersaults while trying to convince her brother to talk to Maggie, all without telling him she knows that Richard goes to AA. She made a pledge, after all.

While trying to piece her kaleidoscopic memories of Ellis back together, Meredith grills Richard about the conversation she saw them have by the carousel (which we saw in the season premiere). He lies and says he doesn't remember the specifics, but does promise to dig out Ellis' journals for her.

In another flashback, we see Ellis tell Richard that she's ready to leave her husband Thatcher for him and then try to bully Richard into doing the same with Adele. He eventually agrees, but their plans to run off into the sunset are derailed after Ellis learns that she's on the shortlist for the Harper Avery Award, and Richard pouts.

Back in 2014, Meredith channels the Ghost of Ellis Grey to save the not-pregnant girl's life (cue jarring flashbacks), and it turns out the girl and her mother are undocumented immigrants. How cute is it that Alex used to braid his sister's hair?! The mother waited to bring her daughter to a hospital because she was worried they would be sent back to their home country, where one or both of them would likely be forced into prostitution. Meredith first calls Child Protective Services, but then shoos them away after hearing the mother's real-life "Would You Rather" plight.

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MerDer continue their fight, with Meredith (rightfully) voicing her resentment of Derek for comparing her to Ellis. "You could do worse than compare me to a brilliant surgeon," she notes. "But you meant it in the sense that I'm cold, and ambitious, and selfish, a horrible wife and mother." Well said, Meredith. They finally start hash out their issues, with Derek saying he gave up the NIH job for Meredith and Meredith essentially telling him to go the hell to D.C. if he wants to.

After receiving the cold shoulder from Meredith, Derek asks Maggie why she's leaving. When she tells him she's Richard's daughter and Meredith's half-sister, Derek looks like a kid on Christmas morning.

"Meredith is terrible with sisters (ha!) ... and I'm not. I have a bunch," he says sweetly. He runs over to Maggie and gives her a hug, which makes my heart melt. I'm guessing this is more in line with the reaction Maggie wanted when she came looking for her blood relatives. Derek later insists on a truce with Meredith and cautions her against losing a(nother) sister.

Meanwhile, Bailey is still trying to figure out why Maggie's leaving — and why Richard snaps at her every time she mentions Maggie's name. "I think she's leaving because of you," she tells Richard accusingly (Good detective work, Bailey!), but is then thrilled when he finally fesses up that Maggie is his and Ellis' daughter. Why? Because she thought Maggie was leaving because Richard had had sex with her. (Ewwwwww.)

Richard admits that he felt jealous upon learning of Ellis' Harper Avery nomination, and tells Meredith that what transpired during the carousel convo was him telling Ellis he wasn't going to leave Adele — and that's what led to Ellis' suicide attempt. Was anyone else kind of unnerved by Baby Meredith calmly telling the 911 operator, "My mommy tried to kill herself," and then gently placing the receiver back? Adult Meredith's memories finally coalesce, and she remembers her mother giving birth to Maggie in a hospital. (When Ellis' water broke, it scared her because it reminded her of the blood dripping when Ellis cut her wrists.)

Meredith tells Maggie she can quit if she wants, but she wants to show her something first: Ellis' journals, which lack wine stains after she realized she was pregnant with Maggie. Meredith takes this as a sign that Ellis really did have Maggie's best interests at heart. (I think we can all agree Ellis Grey was a pretty terrible mother, but if it helps Meredith's psyche to adopt a "she did the best she could" view of her mom's parenting style, then more power to her.)

As the episode ends, we see Ellis concluding her videotaped speech by saying that she dedicated her Harper Avery to "all the women surgeons who would come after me" — a.k.a. HER DAUGHTERS.

So, what did you think of "Only Mama Knows"? Did your opinion of Ellis change at all after seeing these flashbacks? Where do you think Maggie and Meredith will go from here? And what's in store for Callie and Arizona next week? Sound off in the comments!

Grey's Anatomy airs Thursdays at 8/7c on ABC.